Interior Vertexes and Faces Post Boolean
Answer: Stop trying to use booleans so much...

I moved away from using the boolean operators for the heavy lifting and instead used a curve with a screw modifier as the base and then began to manually build the rest of the object by hand.  I was careful to check for non-manifold elements along the way.  The hex head top was added with a boolean however.  

I think it came out quite nice.

That being said, there are a few things that look as though they could be improved.

I have attached the final blend file for those who are curious.